Temperature control pack and method

ABSTRACT

A temperature control pack for refrigerating a shipping container includes a mass of gel material which is shape-retaining at room temperature, and is configured as a relatively thick rectangular solid. The mass of gel material is enclosed in a first plastic film bag, and also in a second plastic film bag providing a sheath about the first bag, and also enclosing a quantity of air to provide an insulating and cushioning air space between the bags. Especially at the ends of the mass of gel material and surrounding bags, an air cushion space is provided in order to safeguard the plastic bags against bursting caused by “water hammer” effect from dropping, impacts, or jarring of the shipping container. The thick rectangular shape of the mass of gel material, along with the pair of plastic film bags, in combination with the insulating air space, provide a leak-resistant temperature control pack with increased refrigerating endurance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an improved temperature control pack, and particularly relates to such a pack which may be frozen and placed along with items requiring sub-ambient temperatures (i.e., refrigeration) into a shipping container. The frozen temperature control pack maintains the items at a refrigerated temperature during shipping, and preserves the items against high ambient temperatures.

2. Related Technology

The use of water ice, dry ice, and so-called gel-packs, or blue-ice packages in order to provide refrigeration for items during shipping has been known for a long time. However, each of these expedients has disadvantages. Water ice melts, and the resulting melt water presents a possibility of soaking into the items being shipped, or of leaking out of the shipping container.

Dry ice does not produce melt water, but it does provide temperatures which are too cold in many cases. The risk in the use of dry ice is that items shipped along with dry ice may be undesirably frozen. As a result, many shipments using dry ice refrigerant must include arrangements to insulate the dry ice from the items being shipped.

Similarly, the so-called “blue-ice packages present a leakage risk, and also may present a moisture hazard to items being shipped, as condensate forms on the blue-ice packages, and may contaminate the shipped items. Additionally, the blue-ice packages themselves present a soiling or spoiling risk, as these packages are subject to leakage and bursting due to the shipping container being dropped or subjected to impacts during shipping. The blue-ice containers generally contain a gel material which can leak out of the packages and soil, contaminate, or spoil items being shipped with the packages. Also, in order to prevent condensate water from contaminating or soiling the items being shipped, it is common for shippers to use a desiccant towel or wrapping about the gel pack to absorb and contain condensation.

SUMMARY OF THE INVENTION

In view of the deficiencies of the conventional related technology, it is an object of this invention to overcome one or more of these deficiencies.

Particularly, an object for this invention is to provide a temperature control pack with improved endurance compared to an equivalent weight of conventional gel packs.

Another object for this invention is to provide a temperature control pack that is burst resistant.

To this end, the present invention provides a temperature control pack including a mass of gel material, a first bag enclosing this mass of temperature control material, and a second bag enclosing the first bag and a surrounding quantity of air to form an air space between the first bag and the second bag.

Further, the present invention provides a method of making the inventive temperature control pack.

Other objects, features, and advantages of the present invention will be apparent to those skilled in the art from a consideration of the following detailed description of a preferred exemplary embodiment thereof taken in conjunction with the associated figures which will first be described briefly.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

FIG. 1 is a perspective view of an improved temperature control pack according to this invention;

FIG. 2 illustrates a step in the method of making an improved temperature control pack according to this invention;

FIG. 3 illustrates a step subsequent to that of FIG. 2 in the method of making an improved temperature control pack according to this invention;

FIG. 3A shows a manufacturing intermediate article resulting from the step illustrated in FIG. 3; and

FIG. 4 illustrates a step subsequent to that of FIG. 3

DETAILED DESCRIPTION OF EXEMPLARY PREFERRED EMBODIMENTS OF THE INVENTION

While the present invention may be embodied in many different forms, disclosed herein is one specific exemplary embodiment which illustrates and explains the principles of the invention. In conjunction with the description of this embodiment, a method of making the product is described. It should be emphasized that the present invention is not limited to the specific embodiment illustrated. That is, those skilled in the relevant arts will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof.

Turning now to FIG. 1, an improved temperature control or refrigeration pack 10 is illustrated. It will be noted that this temperature control pack 10 includes a generally flat and rectangular (i.e., prismatic) body 12, which includes and is encompassed by a loose fitting outer sheath or bag 14 of heavy, leak-resistant plastic sheet or film. Preferably, the outer bag or sheath 14 is made in a tubular shape, from a tube of plastic film, and is closed respectively at each of its opposite ends by a simple transverse heat-sealed seam 16. This seam 16 is made by simply pinching together the material of the bag 14, and then forming a transverse heat seal in the plastic film of the bag 14. Most preferably, the bag 14 is formed of a tube of polyethylene film material having a wall thickness of about 4 mils (i.e., 0.004 inch). Alternatively, a laminated film, or so called structured film, such as one including a layer of polyethylene and a layer of nylon, can be used to make the bag 14. Such a structured film for the bag 14 provides greatly increased cut resistance and greater strength for the bag 14. Further, those skilled in the pertinent arts will understand that the temperature control pack 10 may be frozen and used like water ice, or like dry ice in the refrigeration of items which require sub-ambient temperatures (i.e., refrigeration) during shipping. However, as will be further explained, the temperature control pack 10 has a greater endurance than conventional gel packs, is not nearly so subject to the formation of condensate water as are conventional gel packs, and breakage of the temperature control pack 10 with attendant leakage of the gel material is substantially prevented.

Considering now FIG. 2, a step in the process or method of making a temperature control pack 10 is illustrated. In FIG. 2, it is seen that a prismatic mass 18 of shape-retaining gel material is provided. This mass 18 of gel material is distinct from the more shape-less gel used in conventional gel packs in that it is both shape-retaining, and is of greater thickness in comparison to its width and length than conventional gel packs. With respect to the shape-retaining nature of the gel material 18, this material is made of about 93% water, and includes starch and a polymer sufficient to give it a shape-retaining nature at room temperature. Of course, this shape is retained when the gel pack 10 is frozen, so that the gel pack 10 has essentially the size and shape of the mass 18 of gel material (plus an increment of size as will be explained below). The mass 18 of gel material (if it is considered to have a thickness of one unit) has a width of substantially about 3 units, and a length of substantially about 3.7 units. More particularly, a preferred embodiment of the present invention utilizes a mass 18 having a thickness of about 2 inches, a width of about 6 and ¼ inch, and a length of about 7 and 12 inch. This rectangular prismatic shape for the mass 18 provides a substantially greater thickness in comparison to the length and width of the mass 18 than is the case with conventional gel packs. A result of this greater thickness for the mass 18 is that when it is frozen and used to provide refrigeration for items being shipped, it has a self-insulating quality. Another way of stating this concept is that the mass 18 has an increased mass in comparison to its surface area, and so melts more slowly than an equivalent weight of conventional gel packs. Those ordinarily skilled in the pertinent arts will understand that in terms of mass versus surface area, a sphere is the ideal shape for the mass of gel 18. However, a sphere does not pack well in a cardboard box or insulated container, which is generally rectangular. So, if a rectangular solid is to be used for the mass 18, a cube would be the next most desirable shape. But again, a cube does not pack well. The mass 18 is a selected compromise shape of prismatic (i.e., rectangular) solid. The mass 18 has proportions of about 1 unit in thickness to about 3 units in width, to about 3.7 units in length. The shape for mass 18 is selected as a desirably convenient shape for packing in rectangular cardboard boxes and insulated containers along with items to be shipped, while still providing a high ratio of mass to surface area. As a result, the gel pack 10 provides greater endurance during shipping of refrigerated items than would be obtained with an equivalent weight of conventional gel packs.

Further, the mass 18 is seen in FIG. 2 to be inserted into a first bag or wrapping 20 of plastic film material 22. Most preferably, the plastic film material 22 is made in the form of a tube with no side seam, and with open ends. In FIG. 2, it is seen that the closure 24 of the bag 20 at the end away from the viewer has already been formed and heat sealed. Importantly, this closure 24 of the bag 20 is made as a compact or tightly fitted, gusseted or mitered closure, which is heat sealed, and then lays flat against the closed end of the bag 20 and against the contained mass 18 of gel material. As is seen in FIG. 3, the respective closure 24 at the end of bag 20 toward the viewer of FIGS. 2 and 3 is formed in the same way, by first creasing inwardly the material 22 of the bag 20 along the thickness of mass 18, and then capturing this creased material between the layers of material 22 running along the opposite faces of the mass 18. As so formed, the seam is then heat sealed to form the closure 24. And, during this heat sealing operation, the closure is wrapped or folded substantially flat against the end of the mass 18, so that the closures 24 lays flat relative to this mass 18 (i.e., along the end of mass 18), as is best seen in FIG. 3A.

Next, FIG. 4 illustrates that the manufacturing intermediate article seen in FIG. 3A (i.e., the mass 18 enclosed in first bag 20 with end closures 24 formed to lay flat against the ends of the mass 18) is inserted into the outer sheath or bag 14. As is seen in FIG. 4, the outer bag 14 already has one of the seams 16 formed, and the end of the bag 14 toward the viewer is open to receive the mass 18 in bag 20. Importantly, during the insertion of bag 20 into outer sheath 14, no attempt or effort is made to exclude ambient air. In fact, a quantity of ambient air is intentionally left inside of bag 14 and about the inner bag 20 (i.e., containing mass 18). Thus, when the second seam 16 is formed in outer bag or sheath 14 (forming the finished temperature control pack seen in FIG. 1), an air space (and quantity of air) is trapped within the temperature control pack 10 between the sheath 14 and the inner bag 20. This air space surrounds the mass of gel 18, and serves to provide an insulation which has several salutary effects. First, the insulation provided by the trapped air space between the bags 14 and 20 serves to reduce or substantially eliminate the formation of condensation on the outside of the temperature control pack 10. As a result, the use of desiccant towels to control or contain condensate water may be eliminated or reduced substantially. Further, the insulating air space between the bags 14 and 20 provides an increased R value (heat transfer resistance) between the mass 18 of gel and the environment around the temperature control pack 10. The result is two fold. First, items packed for shipping close to the temperature control pack are much less likely to be frozen. So, more efficient use of available space and volume within a shipping container may be made. Secondly, the endurance of the temperature control pack is increased in comparison to an equal weight of conventional gel packs. So, longer shipping times may be successfully accomplished by use of the temperature control pack 10 in comparison with an equal weight of conventional gel packs.

Further to the above, it will be seen that the temperature control pack has several features which cooperatively reduce or eliminate bursting of the pack as a result of a shipping container being dropped or subjected to impact or jarring during shipping. It will be understood that such a dropping, impact, or jarring is more likely to cause a bursting of a gel pack late in a shipping transport, rather than early in the trip, because at a later time the gel will be more melted, and will be more fluid. However, the shape-retaining gel mass 18 is less fluid, and is less subject to the formation of a compression wave or surge in the material than is conventional refrigerating gel. That is, a “water hammer” effect is less likely to form in the mass 18 than is the case with conventional gel packs with their more fluid gel material. Of course, this “water hammer” risk is only a concern when the gel pack is melted or nearly melted. Such a surge or wave cannot form in the frozen gel material.

Secondly, the inner and outer bags 20 and 14 tend to reinforce one another so that the likelihood of breakage of either bag is reduced. This effect is assisted by the air space trapped between the bags 14 and 20 which also tends to form an “air pillow” or air cushion of trapped air which mitigates the effect of dropping, impact, or jarring on the gel pack 10. Especially, it is an important feature of the gel pack 10 that the end of mass 18 with seam 24 is piston-like within bag 14, while the opposite ends of bag 14 has a pocket or space (arrowed with the numeral 26 on FIG. 1) which is generally triangular in cross section adjacent to the seams 16. Thus, in the event that an acceleration due to dropping, an impact, or jarring is directed along the length of the pack 10, the motions of the mass 18 (snugly held within bag 20) are cushioned by the air trapped at either end of and within the bag 14 and particularly that air within space 26. Thus, any “water hammer” effect in the gel 18 which might tend to burst one or both of the bags 14 and 20 is mitigated by the air cushion effect cooperatively formed between and at the ends of the bags 14 and 20. And finally, in the event that the inner bag 20 is breached by a severe drop, impact or jarring of the gel pack 10, the gel material 18 is less likely to leak out because of its shape-retaining nature, and the fact that the outer bag 14 is likely to remain intact and free of leaks.

All of these factors combine to provide a temperature control pack which has greater refrigerating endurance, is less likely to form condensate water, is less likely to be burst or to leak as a result of dropping, impacts, or jarring of a shipping container, and also has the advantage that it is less likely to freeze of over cool items packed into a shipping container along with the pack 10.

Because the foregoing description of the present invention discloses only particularly preferred exemplary embodiments of the invention, it is to be understood that other variations are recognized as being within the scope of the present invention. Accordingly, the present invention is not limited to the particular embodiment which has been described in detail herein. Rather, reference should be made to the appended claims to define the scope and content of the present invention. 

1. A temperature control pack comprising: a mass of gel material, a first bag enclosing said mass of gel material, and a second bag enclosing said first bag and a surrounding quantity of air to form an air space between said first bag and said second bag.
 2. A temperature control pack according to claim 1 wherein said mass of gel material is shape-retaining and is configured at a rectangular solid, and said second bag defines in cooperation with said first bag a pair of opposite air cushion spaces each interposed between an end of said mass of gel material and an end of said second bag.
 3. A temperature control pack according to claim 2 wherein said first bag is configured as a tube of plastic film material enclosing said mass of gel material, and said first bag defines a gusseted seam which is heat sealed and lays substantially flat against an end surface of said rectangular solid of shape-retaining gel material.
 4. A temperature control pack according to claim 2 wherein said second bag is configured as a tube of plastic film material enclosing said second bag and said mass of gel material, and said second bad defines a transverse heat sealed seam that is spaced from an end of said mass of gel material and from said gusseted seam of said first bag, thus to cooperatively define one of said opposite pair of air cushion spaces.
 5. A temperature control pack according to claim 1 wherein said mass of gel material is shape-retaining, and includes about 93 percent water, starch, and a polymer sufficient to render said mass of gel material shape-retaining.
 6. A temperature control pack according to claim 1 wherein said mass of gel material has proportions of about 1:3:3.7.
 7. A temperature control pack comprising: a mass of gel material which is shape-retaining at room temperature, a first bag sealingly enclosing said mass of gel material, and a second bag sealingly enclosing said first bag and said gel material.
 8. A temperature control pack according to claim 7 wherein said second bag defines in cooperation with said first bag an interposed air space confining a quantity of air between said first bag and said second bag.
 9. A temperature control pack according to claim 8 wherein said mass of gel material is shape-retaining at room temperature, and includes about 93 percent water, starch, and a polymer sufficient to render said mass of gel material shape-retaining.
 10. A temperature control pack according to claim 7 wherein said mass of gel material has proportions of about 1:3:3.7.
 11. A method of making a temperature control pack comprising steps of: providing a mass of gel material which is shape-retaining at room temperature, enclosing said mass of gel material sealingly in a first bag, and providing a second bag sealingly enclosing said first bag and said mass of gel material.
 12. The method of claim 11 further including the steps of utilizing said second bag to sealingly enclose both said mass of gel material within said first bag, along with a surrounding quantity of air forming an air space between said first bag and said second bag.
 13. The method of claim 11 further including the steps of providing for said mass of gel material to be shape-retaining at room temperature, and configuring said mass of gel material as a rectangular solid.
 14. The method of claim 11 further including the steps of utilizing said second bag to define in cooperation with said first bag a pair of opposite air cushion spaces each interposed between an end of said mass of gel material and an end of said second bag.
 15. The method of claim 11 further including the steps of configuring said first bag as a tube of plastic film material enclosing said mass of gel material, and said first bag defines a gusseted seam which is heat sealed and lays substantially flat against an end surface of said rectangular solid of shape-retaining gel material.
 16. The method of claim 15 further including the steps of configuring said second bag as a tube of plastic film material enclosing said first bag and said mass of gel material, and configuring said second bad to define a pair of transverse heat sealed seams that are each spaced from a respective end of said mass of gel material and from said gusseted seams of said first bag, thus to cooperatively define said opposite pair of air cushion spaces.
 17. A temperature control pack made according to the method of claim
 11. 18. A temperature control pack made according to the method of claim
 16. 19. A temperature control pack comprising: a mass of gel material which is generally of rectangular solid shape, and is shape-retaining at room temperature, said mass of gel material including water, a starch, and a polymer sufficient to render said gel material shape-retaining at room temperature; a first bag of plastic film material enclosing said mass of gel material, said first bag being configured as a tube of plastic film receiving said rectangular mass of gel material, and defining a pair of opposite gusseted heat-sealed seams each laying substantially flat against a respective end surface of said rectangular mass of gel material; a second bag enclosing said first bag and a surrounding quantity of air to form an air space between said first bag and said second bag, said second bag also being configured as a tube of plastic film material receiving said first bag and said mass of gel material, and said second bag defining an opposite pair of transverse heat-sealed seams each being spaced from a respective end of said mass of gel material and cooperatively defining a respective air cushion space at a respective end of said temperature control pack.
 20. A temperature control pack according to claim 19 wherein said mass of gel material includes about 93 percent water, starch, and polymer sufficient to render said mass of gel material shape-retaining at room temperature.
 21. A method of using a temperature control pack, said method comprising steps of: providing said temperature control pack with a mass of gel material which is generally of rectangular solid shape, and providing for said mass of gel material to be shape-retaining at room temperature, providing for said mass of gel material to include water, a starch, and a polymer sufficient to render said gel material shape-retaining at room temperature; enclosing said mass of gel material in a first bag of plastic film material, configuring said first bag as a tube of plastic film receiving said rectangular mass of gel material, and defining a pair of opposite gusseted heat-sealed seams in said tube of plastic film so that each seam lays substantially flat against a respective end surface of said rectangular mass of gel material; providing a second bag of plastic film enclosing said first bag, said mass of gel material, and also a surrounding quantity of air to form an air space between said first bag and said second bag, configuring said second bag also as a tube of plastic film material, and utilizing said second bag to define an opposite pair of transverse heat-sealed seams each being spaced from a respective end of said mass of gel material and cooperatively defining a respective air cushion space at a respective end of said temperature control pack; freezing said temperature control pack and packaging the frozen temperature control pack inside of an insulated container along with items to be shipped; and utilizing an increased R value provided by said first and second bags in combination with said air space and effective between said mass of gel material and the surroundings of said temperature control pack within the container to both mitigate condensation of water on said temperature control pack, and to increase the refrigerating endurance of said temperature control pack.
 22. The method of claim 20 further including the step of providing for said mass of gel material to includes about 93 percent water, starch, and polymer sufficient to render said mass of gel material shape-retaining at room temperature.
 23. A temperature control pack comprising: a mass of gel material, a first bag enclosing said mass of gel material, and a second bag enclosing said first bag, and wherein said mass of gel material has proportions of about 1 unit in thickness: to about 3 units in width: to about 3.7 units in length
 24. The temperature control pack according to claim 23 wherein said mass of gel material includes about 93 percent water, starch, and polymer sufficient to render said mass of gel material shape-retaining at room temperature. 